Sand and gravel injector for oil well servicing



W. R. REED May 10, 1955 SAND AND GRAVEL INJECTOR FOR OIL WELL SERVICINGFiled Jan. 12, 1953 r NVENTOR. ZZ/ade' E. jieed,

W YK. P HN N 4 N 5 M av f ATTU RN EYS United States Patent SAND ANDGRAVEL INJECTOR FOR OlL WELL This invention relates to oil wellservicing equipment, and more particularly to an assembly for injectingsand and gravel into oil wells.

The object of the invention is to provide an assembly for use ininjecting sand and gravel into oil wells in order to increase theproductive capacity of the wells.

Heretofore in oil well operations, methods known as hyda-fracking andstrata-fracking have been used. Thus, according to these methods crudeoil or gasoline jell is pumped into the well tubing or casing under highpressure in the neighborhood of 2000 to 3000 pounds per square inch, andthis crude oil or gasoline jell has mixed therewith a hard sand whichincludes grains of about .025 inch in diameter. In actual practice amixture of about one pound of sand to a gallon of fluid is used and thishigh pressure cracks up the oil formation wherep by the sand lodges inthe crevices to prevent the crevices from coming back together after thepressure is released. Thus, there is formed a multitude of leaks in theoil formation to thereby create a marked increase in the production ofthe well. However, one difficulty with this process is that the sandmixture passes through the high pressure pump to cause a great amount ofdamage to the pump and also, another disadvantage is that the size ofthe grains of sand is limited and'if-sand or gravel having a largerdiameter is used the crevices could be held further apart afterreleasing the pressure.

It is, accordingly, another object of the invention to produce anassembly which will eliminate the foregoing disadvantages.

A further object of the invention is to provide a sand and gravelinjector for oil wells which. is extremely simple and inexpensive tomanufacture.

Other objects and advantages will be apparent during the course of thefollowing description.

In the accompanying drawings, forming a part of this application, and inwhich like numerals are used to designate like parts throughout the samethe single view is a view, with parts broken away and in section showingthe present invention.

Referring in detail to the drawing, the numeral 1 designates a highpressure hydraulic pump which can be of conventional constructionproviding it will produce pressures up to several thousand pounds persquare inch. The assembly further includes a small capacity booster pump2, and the numerals 3 and 4 designate cylinders of heavy constructionwhich will withstand the required high pressures. Each of the cylinders3 and 4 are adapted to hold a quantity of sand and gravel for a purposeto be later described, and this sand and gravel is indicated by theletter S. Reciprocably or slidably arranged in each of the cylinders 3and 4 is a piston 5, and each of the pistons 5 includes a pair of rubbercups 25 which have a plate 26 therebetween. A conduit 28 leads from themain pump 1 to a conduit 27, and one end of the conduit 27 is adapted tolead to the oil well casing. A bypass or branch conduit 29 is connectedto the conduit 27, and a valve 8 is interposed in the bypass 29.

A pair of valves 6 and 7 are interposed in the conduit 27 for a purposeto be later described. A pair of conduits or pipes 30 and 31 lead fromthe conduit 27 to one end of the cylinder 3, while a similar pair of conduits 33 and 34 lead from the conduit 27 to the other cylinder 4. Avalve 9 is arranged in the conduit 30, a valve 10 is arranged in theconduit 31, and valves 18 and 19 are arranged in the conduits 33 and 34,respectively.

A high pressure tube or conduit 12 has one end connected to a detachableor removable head 17 which is mounted on the other end of each of thecylinders 3 and 4. One end of the tube 12 communicates with a tube '14which is adapted to convey a certain amount of hydraulic fluid or oilinto the interior of the cylinders so that the sand and gravel will havea sufficient quantity of oil intermixed therewith to prevent the sandand gravel from solidifying. The tube 14 may be slidably mounted in apacking or stufiing box 13 which is arranged on an end of each of theheads 17. A pair of valves 11 and are interposed in the high pressurehose or conduit 12. For the purposes of clarity, the valves in the hose12 for the cylinder 3 are indicated by the numerals 11 and 15, while thevalves in the hose 12 for the other cylinder 4 are indicated by thenumerals and 21.

There is further provided a conduit 35 which extends from each of theheads 17, and the conduit 35 is connected to a hose or conduit 45 whichleads to a supply tank 43. A valve 22 is interposed in each of theconduits 35.

The numeral 42 designates an air line or conduit which is adapted toconvey air under pressure from a suitable source of supply. A conduit 36leads from the air line 42 to one end of the cylinder 3, and a similarconduit 41 connects the cylinder .4 to the air line 42. A valve 23 isinterposed in the conduit 36, and a value is interposed in the conduit.41. A bleeder line 37 having a valve 24 therein leads from the cylinder3, and a similar bleeder line 39 having a valve 38 therein leads fromthe other cylinder 4. v

The conduits 36 and 41 leading from .the air line 42 are adapted tosupply compressed. air to the cylinders 3 and 4 when the pistons 5 areto be forced back to their originalpositions p The conduits 35 havingthe valves 22 therein communicate with the supply tank 43 through theconduit so that the hydraulic fluid or oil can be returned to the supplytank 43. A conduit 44 interconnects the supply tank 43 and the mainpump 1. Each of the pistons 5 is provided with a central opening 32whereby fluid passing from the tubing 14 can pass through the cylinder 4and intermix with the sand or gravel S.

From the foregoing, it is apparent that a sand and gravel injectingmechanism for oil well servicing has been provided. In use, crude oil orgasoline jell under high pressure is pumped into the well tubing orcasing and a mixture of hard sand is pumped in with the oil or jell.This high pressure cracks up the oil formation and the sand lodges inthe crevices to prevent the crevices from coming back together after thepressure is released to thereby form a multitude of leaks in the oilformation so that a marked increase in the wells production isaccomplished. By means of the present invention the sand mixture willnot go through the high pressure pump 1 so that there will be no damageto the pump during the operation. Also, the sand and gravel can be oflarger diameter grains than is ordinarily used.

The operation of the assembly is as follows: the cylinders 3 and 4 arefirst loaded with the desired quantity of sand or gravel S and this sandor gravel may be initally saturated with the fluid to be pumped. Thepump 1 may be driven by means of a power take-off on a truck andpressure is built up to the bottom of the well. At this time the valves6 and 7 are open. Assuming that the cylinder 3 on the left is to beemptied first, the stops or valves 9 and 10 are opened and the valve 6is closed to thereby cause the discharge stream to pass through the endof the cylinder 3 through the conduit 31, then through the conduit 27 inthe direction of the arrows. Next, the valve 11 is opened and the bypassvalve 8 is closed slightly. This causes the fluid to flow through thehydraulic hose 12 and through the tubing 14 and into the cylinder 3behind the sand and gravel. The tubing 14 passes through the stuffingbox 13 and is connected to the discharge line of the booster pump 2 bymeans of a suitable fitting. The valve 15 is also interposed in the line12 and the line 12 leads to the cylinder head 17.

The fluid passing through the tubing 14 enters the cylinder 3 throughthe opening 32 and this fluid keeps the sand and gravel loosened up inthe cylinder to thereby prevent the sand and gravel from becoming lockedor solidified. When the valve 15 is opened, the piston moves forwardlyin the cylinder 3 and since the discharge from the pump 1 is passingthrough the end of the cylinder, the sand and gravel S will be movedforwardly and will be carried through the outlet 31, to the conduit 27and into the well. The amount of pressure and quantity of fluid requiredto keep the sand loosened up and the forward travel of the piston 5 iscontrolled by the bypass valve 8 and the valves 11 and 15. Suitablegraduations or markings can be arranged on the tubing 14 so that anindication will be given as to the required amount of gravel per gallonof fluid being used.

After the piston 5 in the cylinder 3 has reached the extreme forwardtravel in its cylinder, the valve 6 is opened and the valves 9 and areclosed. Then, the bypass valve 8 is opened and the valves 11 and areclosed and this completely cuts ofi the cylinder 3. Next, the valves 18and 19 for the cylinder 4 are opened and the valve 7 is closed tothereby cause the fluid to pass through the end of the cylinder, thiscylinder having been previously loaded for operation. Next, the valve 20is opened, the valve 8 is closed slightly and the valve 21 is openedslightly. This process is repeated for the cylinder 4 in the same manneras the previously described cylinder 3.

When the cylinder 3 is to be reloaded, the valve 22 is opened to permitfluid behind the piston 5 to drain back to the supply tank 43. The valve23 is then opened and air pressure from the hose 42 is injected into theforward end of the cylinder 3 to force the piston 5 back to the oppositeend of the cylinder and force the remaining fluid out through theconduit 35, then into the conduit and back to the supply tank 43. Theair is shut off and the pressure released through the bleeder line 37.The cylinder heads 17 can be removed and also the piston 5 can beremoved. Thus, the cylinder head can be removed when the cylinder is tobe reloaded with sand and gravel. After the cylinder is refilled withthe desired quantity of sand and gravel, the piston and head arereplaced and the cylinders are ready for operation. Although theapparatus has been shown to include two cylinders, it is to beunderstood that more than two cylinders can be used and the parts can beadjusted and controlled so that there is a minimum amount of delaybetween discharge of the cylinders so that the cycle is continuous. Theconnections to the removable heads on the cylinders are high pressureconduits or hoses so that there will be no danger in using such parts.

I claim:

In a sand and gravel injector for oil well servicing equipment, a mainpump, a booster pump, a pair of cylinders adapted to hold a quantity ofsand and gravel, a piston reciprocably arranged in each of saidcylinders and each of said pistons being provided with a central openingtherein, a first conduit leading from said main pump, a second conduitconnected to said first conduit, said second conduit adapted to lead toan oil well casing, a bypass line connected to said second conduit andhaving a valve therein, a pair of valves interposed in said secondconduit, a first pair of pipes leading from said second conduit to oneend of one of said cylinders, a second pair of pipes leading from saidsecond conduit to an end of said other cylinder, valves arranged in eachof said pipes, a head mounted on the other end of each of saidcylinders, a third and fourth conduit connected to said second conduitand having one end connected to said heads and their other endscommunicating with the openings in said pistons, valves in said thirdand fourth conduits, fifth conduits connecting said heads to said supplytank, a sixth conduit adapted to be connected to a source of air underpressure and communicating with said cylinders, bleeder lines connectedto said cylinders, and a seventh conduit connecting said supply tank tosaid main pump.

References Cited in the file of this patent UNITED STATES PATENTS1,975,162 Layne Oct. 2, 1934 2,077,898 Roltf Apr. 20, 1937 2,443,146Pyles June 8, 1948

